1. Field of the Invention
This invention relates to an integrated optical transceiver and more particularly a transceiver employing an inter cavity demultiplexer resonator for use in optical communication systems.
2. Background of the Related Art
Multi-wavelength optical communication networks can significantly increase transmission capacity, enhance system flexibility and allow for more flexible and novel system management schemes. A major problem with the costeffective effective realizatiion of such systems is the achievement of stable multiwavelength wavelength transceiver and detector devices with accurate channel wavelength definition and low temperature sensitivity. The latter is to conserve wavelength registration and so allow communication of different devices at different parts of the system that may be at different temperatures. Wavelength selected Distributed Feed Back (DFB) devices used in the prior art suffer from requiring accurate temperature control, lack of wavelength definition on fabrication and high coupling losses on coupling the channels into a single output.
Integration of active or passive wavelength selective devices within laser or detector structures to form integrated multi-wavelength transmitter or receiver devices capable of transmitting or detecting a number of wavelengths simultaneously has been proposed. It is also known that such wavelength selective devices can be formed inside a laser cavity to allow laser oscillation on a number of wavelength channels. The wavelength selective device used in such arrangements is usually a grating based structure typically integrated with lenses or mirrors to perform the required beam manipulation.
The present invention aims to improve upon such devices by providing an integrated multi-wavelength transceiver.
According to a first aspect of the present invention there is provided an integrated optical transceiver comprising a laser cavity formed between first and second feedback elements, wavelength selective means within the laser cavity for determining a lasing wavelength of the laser cavity and light receiving means, at least one of the feedback elements being partially transmissive at the lasing wavelength so as to permit the transceiver to emit radiation of the lasing wavelength, and the wavelength selective means being arranged to receive light through one of the feedback elements and transmit light of a selected wavelength, differing from the lasing wavelength, to the light receiving means.
Such a transceiver is capable of detecting incoming data on one or a set of wavelengths and simultaneously transmitting data on a different wavelength or set of wavelengths.
The wavelength selective means determines the lasing wavelength by being part of the laser cavity and also determines the selected wavelength transmitted to the light receiving means, and therefore determines both the wavelength transmitted by the transceiver and the wavelength received by the transceiver.
According to another aspect of the invention there is provided a matched pair of such transceivers.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.